1. Field of the Invention
The present invention relates to a BGP route evaluation method for quantitatively evaluating a BGP route on the basis of an active rate, and a device therefor.
2. Description of the Related Art
The Internet is the set of domains each of which includes a small-scale autonomous network system (hereinafter referred to as “AS”), which is held and operated by each organization, as a unit. The respective domains are mutually connected to other specified domain by peering using a border gate protocol (hereinafter referred to as “BGP”).
As for a method of enhancing the reliability of external connection using the BGP, a non-patent document 1 discloses multihoming by which connection to a multiple ASs is established at the same time to ensure an alternative route at the time of interference. The using of the multihoming can enhance the availability of external connection and hence can enhance the reliability of the external connection. A non-patent document 2 discloses a best-path selecting algorism in a BGP.
[Non-Patent document 1] IPv4 Multihoming Practices and Limitations, RFC 4116
[Non-Patent document 2] A Border Gateway Protocol 4 (BGP-4), RFC 4271
A traffic transfer in the mutlihoming, in reality, can be achieved only for one destination of connection. The switching of the connection at the time of interference raises the problem of communication interruption for a specified time. To further enhance the availability, it is desired to select a path of the lowest failure rate, but the best-path selecting algorism disclosed in the non-patent document 2 gives higher priority to the shortest path except for control by an operation policy and hence cannot select a path of a lower failure rate.